Blood volume determination and sensor calibration

• US 7,734,322 B2
• Filed: 02/02/2004
• Issued: 06/08/2010
• Est. Priority Date: 10/14/1997
• Status: Active Grant

• Current Assignee: Transonic Systems, Inc. (Measurement Innovations Corp.)
• Original Assignee: Transonic Systems, Inc. (Measurement Innovations Corp.)
• Inventors: Starostin, Dimitry M., Krivitski, Nikolai M.
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US10/769,834
• Publication Number:
  US 20040158133A1
• Time in Patent Office: 2,318 Days
• Field of Search: 600/310, 600/322, 600/481, 604/4.01, 604/5.01, 604/6.08, 250/252.1, 356/432, 356/441, 356/442
• US Class Current: 600/322
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/0275 using tracers, e.g. dye dilution
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/14557 specially adapted to extracorporeal circuits
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes

Abstract

An apparatus is provided for determining a calibration coefficient of a blood property sensor located in a blood system, wherein the blood system can include a vascular portion and an extracorporeal portion. The blood property sensor can be located in the extracorporeal portion to measure the change in a blood property corresponding to the passing of an indicator. The indicator can include a known amount of an introduced dilution indicator. The controller is provided for determining the calibration coefficient of the blood property sensor corresponding to the introduced dilution indicator in the measured change in the blood property.

Claims

1. A method for calibrating a blood property sensor, the method comprising:

(a) connecting an arterial tubing portion of a dialysis system to withdraw blood from a patient and connecting a venous tubing portion of the dialysis system to deliver blood to the patient;

(b) passing diluted blood having a dilution indicator past the blood property sensor in the venous tubing portion;

(c) determining at least one property of the diluted blood passing the blood property sensor in the venous tubing portion; and

(d) determining a calibration coefficient K of the blood property sensor based on the determined blood property of the diluted blood passing the blood property sensor in the venous tubing portion and the relationship

2. The method of claim 1, further comprising determining a blood volume change corresponding the calibration coefficient.

3. The method of claim 1, further comprising employing an ultrasound sensor as the blood property sensor.

4. The method of claim 1, wherein determining at least one property of the diluted blood includes determining one of protein concentration, saline or electrolyte of the diluted blood.

5. The method of claim 1, wherein determining at least one property of the diluted blood includes measuring one of a photometric, optical, electrical or thermal property of the diluted blood.

6. The method of claim 1, wherein passing a dilution indicator past the blood property sensor includes passing a known volume of the dilution indicator past the blood property sensor.

7. A method for calibrating a blood property sensor in a blood system having a vascular portion and an extracorporeal portion, the method comprising:

(a) introducing an indicator bolus upstream of a blood property sensor in the extracorporeal portion to form diluted blood;

(b) measuring a property of the diluted blood with the blood property sensor in the extracorporeal portion; and

(c) determining a calibration coefficient K of the blood property sensor based on the measured property of the diluted blood and the relationship

8. The method of claim 7, wherein introducing the indicator bolus is effective to change an ultrasound velocity in the diluted blood.

9. The method of claim 7, wherein measuring a property of diluted blood includes measuring one of photometric, optical, electrical or thermal property of the diluted blood.

10. The method of claim 7, wherein measuring a property of diluted blood includes measuring one of protein concentration, saline, ultrasound velocity or electrolyte of the diluted blood.

11. An apparatus for calibrating a blood property sensor in a blood system, comprising:

(a) an extracorporeal portion having a first end adapted to be connected to a vascular portion of the blood system at an upstream end and a second end adapted to be connected to the vascular portion at a downstream end;

(b) a blood property sensor coupled to the extracorporeal portion for detecting a property of diluted blood flowing within the extracorporeal portion; and

(c) means for determining a calibration coefficient K of the blood property sensor based on the detected property of the diluted blood and the relationship

12. The apparatus of claim 11 wherein the blood property sensor is one of a photometric, optical, electrical or thermal sensor.

13. The apparatus of claim 11, wherein the extracorporeal portion includes an arterial length and the blood property sensor is located along the arterial length.

14. An apparatus for calibrating a blood property sensor in a blood system having an extracorporeal portion, comprising:

(a) a blood property sensor coupled to the extracorporeal portion for detecting a property of diluted blood flowing within the extracorporeal portion; and

(b) means connected to the blood property sensor for determining a calibration coefficient K of the blood property sensor based on the detected property of the diluted blood in the extracorporeal portion and the relationship

15. A method of calibrating a blood property sensor in an extracorporeal blood circuit fluidly connected to a vascular blood circuit, the method comprising:

(a) introducing a change to a predetermined blood property;

(b) measuring a corresponding change in the blood property at a blood property sensor in the extracorporeal blood circuit; and

(c) determining a calibration coefficient K of the blood property sensor based on the measured change and the relationship

16. A method of calibrating a blood property sensor in an extracorporeal blood circuit, the method comprising:

(a) introducing a known amount of indicator into an extracorporeal blood circuit;

(b) measuring a change in a blood parameter corresponding to passage of the indicator at a blood property sensor coupled to the extracorporeal blood circuit; and

(c) determining a calibration coefficient K of the blood property sensor based on the measured change and the relationship

17. A method of calibrating a blood property sensor in an extracorporeal blood circuit fluidly connected to a vascular blood circuit, the method comprising:

(a) measuring a blood property of a dilution indicator bolus passing a blood property sensor in the extracorporeal blood circuit; and

(b) determining the calibration coefficient K of the blood property sensor based on the measured blood property and the relationship